The present invention relates to wiper devices and liquid ejection apparatuses.
Inkjet type printers are widely known as liquid ejection apparatuses that eject liquid onto a target from a recording head, or a liquid ejection head, which includes a plurality of nozzles. Specifically, the printer ejects ink from the recording head as the liquid. After having been ejected, the ink may adhere to a portion in the vicinity of a nozzle opening or be splashed by a recording medium, such as a sheet of paper, thus adhering to a nozzle surface or a side surface of the recording head. If the recording head is contaminated by the ink, offset ejection of ink droplets or clogging of the nozzles may occur, leading to printing problems. In order to solve these problems, the printer is normally provided with a wiper device that cleans the nozzle surface and the side surface of the recording head.
For example, a wiper device described in Japanese Laid-Open Patent publication No. 2000-198211 includes a wiper formed of rubber. The wiper is held by a cap holder in such a manner that the wiper is selectively raised and lowered. A slit is defined in the wiper at a position corresponding to a side surface of a recording head. In operation, the wiper slides along the recording head while overlapping the recording head in a vertical direction by an amount of approximately 1 mm. This causes the top surface of the wiper to wipe a nozzle surface defined in the recording head and the slit to wipe off the ink from the side surface of the recording head.
However, in this wiper device, a nozzle surface wiper (the top surface of the wiper), which wipes the nozzle surface of the recording head, and a side surface wiper (the slit of the wiper), which wipes the side surface of the recording head, are formed as an integral body. It is thus impossible to wipe the side surface of the recording head without involving the nozzle surface. In other words, wiping of the side surface and wiping of the nozzle surface of the recording head must be performed always in combination. If the nozzle surface is wiped (wiped dry) when the nozzle surface is free from excessive ink, meniscus of ink in nozzle openings is damaged, thus causing a printing problem. Also, wiping of the side surface of the recording head can be brought about only when cleaning of the nozzle surface is performed. Thus, even when wiping of only the side surface of the recording head is desirable, such operation is not allowed.
In another wiper device described in Japanese Laid-Open Patent Publication No. 2000-198211, a side surface wiper is formed integrally with a cap, which seals a nozzle surface when cleaning a recording head, and independently from a nozzle surface wiper. Exclusive wiping of the side surface of the recording head thus can be performed independently from wiping of the nozzle surface. However, wiping of the side surface of the recording head cannot be performed unless the cap is in capping operation. In other words, the capping operation necessarily causes the wiping of the side surface of the recording head. This increases the frequency of such wiping, thus decreasing the durability of the wiper.